Humidifying gas induction or supply system

ABSTRACT

Water vapor is introduced into an inlet air stream ( 16 ) of an engine ( 12 ), for example, by a pervaporation process through a non-porous hydrophilic membrane ( 18 ). A water reservoir ( 20 ), which can contain contaminated water, provides a vapor pressure gradient across the hydrophilic membrane ( 18 ) into the inlet air stream ( 16 ), while the rate of delivery of the water vapor to a cylinder ( 38 - 40 ) is self-regulated by the rate of flow of air across the membrane. The hydrophilic membrane ( 18 ) therefore also filters the water from the water reservoir ( 20 ) to an extent that pure water vapor is provided to the air inlet stream ( 16 ). Delivery of water vapor can nevertheless be controlled using a hood ( 26 ) that slides over the hydrophilic membrane to limit its exposed surface area. Alternatively, water vapor is introduced into one or more of the gas streams of a fuel cell by separating the gas stream from the wet exhaust gas stream by a hydrophilic membrane such that moisture passes across the membrane to moisten the gas stream and thereby prevent drying out of the proton exchange membrane.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 09/369,803,filed 6 Aug. 1999, now U.S. Pat. No. 6,511,052.

BACKGROUND TO THE INVENTION

This invention relates, in general, to humidifying gas induction orsupply systems and particularly, but not exclusively, to a humidifyingair induction or supply system of an internal combustion engine and ahumidifying gas induction or supply system for a fuel cell.

SUMMARY OF THE PRIOR ART

In energy conversion systems in general, a fuel and an oxidant arecombined to provide energy. In this process, chemical energy isconverted into kinetic energy or electricity, as well as heat.

In internal combustion engines, including two-stroke, four-stroke,rotary and diesel motors for example, fuel-air mixtures are burnt toprovide this chemical energy. Prior to combustion, the fuel may bedispersed into the induction air stream by means of direct injectors orby a carburetor, and the combustion itself may be triggered by anelectrical spark, a glow-wire or simply by the heat of compression ofthe fuel-air mixture. In all internal combustion engines, the suddenincrease in pressure caused by burning a fuel-air mixture in thecombustion chamber causes parts of the engine to move, so impartingkinetic energy to the vehicle powered by the engine.

Many factors control the efficiency with which chemical energy isconverted into useful kinetic energy or electricity, while minimizingthe non-productive heat that is always produced alongside. Key variablesfor maximizing the efficiency of an internal combustion engine includemaximizing the pressure built up during the combustion process andminimizing the temperatures of the induction air and the combustionchamber. A cooler-burning engine also offers the environmental advantageof a reduction in the amount of nitrogen oxides emitted as a by-productby the reaction of atmospheric nitrogen with oxygen species during thecombustion process.

In addition to fuel and air, chemically inert materials may beintroduced into the combustion chamber to absorb heat and generatepressure, thus meeting both of the above requirements for optimizingengine efficiency. In particular, water may be used to fulfil thisfunction.

It is known that the automotive industry, for example, has previouslyused a selective water-injection cooling system for engine cylinders.However, the complexity of such a system and the high cost of itsimplementation have conspired to outweigh the benefits obtained by theprocess for large-scale commercialization. More specifically, waterinjection systems to engine cylinders have previously demanded energyinput, precise control and high operating pressures, with any one ofthese requirements itself placing a significant constraint on potentialimplementation.

Other gas induction or supply systems in which humidification is ofvalue include fuel cells, in particular proton exchange membrane (PEM)fuel cells in which gases are constantly passed over a membrane thatmust be kept damp for optimum performance. Humidification of circulatedair in greenhouses may also be contemplated by use of the followinginvention.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided ahumidifying gas induction or supply system comprising a hydrophilicmembrane surface.

Preferably, the humidifying gas induction or supply system furthercomprises a water reservoir integrally formed with the hydrophilicmembrane surface.

A hood may be arranged to regulate an area of hydrophilic membranesurface exposed to one of the water reservoir and the gas induction orsupply system.

In another aspect of the present invention there is provided an enginecomprising a humidifying air induction or supply system having ahydrophilic membrane surface.

Preferably, the engine further comprises a water reservoir integrallycoupled with the hydrophilic membrane surface.

In a further aspect of the present invention there is provided amotorized vehicle containing a humidifying air induction or supplysystem having a hydrophilic membrane surface.

Preferably, the motorized vehicle further comprises a water reservoircoupled to the hydrophilic membrane surface.

A hood may be arranged to regulate an area of hydrophilic membranesurface exposed to one of the water reservoir and the air inductionsystem.

An exhaust system from the engine expels exhaust gases from the internalcombustion process, and these exhaust gases may be used by aheat-exchanging coil in the water reservoir to heat the water containedin the water reservoir.

In another embodiment, the motorized vehicle further comprises: a fueltank having a hydrophilic membrane surface across which water vaporpervaporates; and a channel juxtaposed the hydrophilic membrane andcoupled to the water reservoir, the channel providing either acondensation trap for water vapor pervaporated from the fuel tank, andwherein the channel is coupled to the water reservoir, or a means ofdirecting the water vapor released by the hydrophilic membrane directlyinto the incoming air stream. However, use of the membrane to bleedwater from a fuel tank may also be actioned independently within aseparate system.

Advantageously, the present invention allows the selective augmentationof water vapor into an air induction system, such as within an engine ofa car, that is achieved easily (in terms of mechanical and controlsimplicity) and at relatively (if not insignificantly) low cost. Indeed,the inclusion of the system of the present invention is extremelydesirable because it limits pollution emissions from car engines (andthe like) while also improving efficiency and performance of suchengines.

In a yet further aspect of the present invention, there is provided afuel cell comprising a humidifying gas induction or supply system havinga hydrophilic membrane surface.

Advantageously the current invention allows the addition of water vaporto one or more of the gas streams of a fuel cell particularly in protonexchange membrane fuel cells, preventing the proton exchange membranefrom drying out and therefore optimizing the fuel cell performance.

Normal tap water or other sources of water (rather than expensivedistilled water) can be used within the systems of the invention, sincethe hydrophilic membrane removes corrosive and damaging impurities.Furthermore, the constant delivery of water vapor into the induction airflow of an engine system avoids all problems associated with theimmiscibility of water and automotive fuels, and also corrosion problemsassociated with the presence of liquid water; and the constant deliveryof water vapor into one or more of the gases of a fuel cell optimizesperformance by preventing the proton exchange membrane from drying out.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will now be describedwith reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a preferred humidifying air intakesystem according to the present invention, the air intake system shownin the context of an engine of a motorized vehicle or the like.

FIG. 2 is a schematic diagram of a preferred humidifying gas inductionor supply system shown in the context of a proton exchange membrane fuelcell.

FIG. 3 is a schematic diagram of the proton exchange membrane fuel cellof FIG. 2 incorporating a further humidifying gas induction or supplysystem.

DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENTS

It has been recognized that engines of cars, for example, develop morepower at a nominal revolution rate on damp mornings, with this increasearising as a consequence of dampness in the air. The present inventionhas identified that there are, in fact, significant advantages andbenefits derived from injecting water (in the form of water vapor) intothe cylinders of an engine, for example. For example, limited amounts ofwater vapor in the cylinder during compression and ignition produces anincreased compression ratio without suffering the detrimental effects of“pinking” or “knocking”. Furthermore, in relation to the overallcombustion process within the cylinder, the water vapor cleans thecombustion chamber and improves fuel burn (by changing the vapor densityand heat capacity of the fuel-air mixture), thereby resulting in loweremissions. Additionally, the presence of water vapor in the combustionchamber has a cooling effect that cools the burn. In other words, thehigh latent heat of vaporization of water causes the engine to runcooler and this therefore results in the lubricants working in a moreefficient manner. Also, with the inclusion of water vapor in cylinders,an improvement in fuel consumption is experienced.

Turning to FIG. 1, a schematic diagram of a preferred humidifying airinduction (or intake) system 10 according to the present invention isshown. The air induction system is, in fact, shown in the context of anengine 12 of a motorized vehicle 14 or the like, although the airinduction system could equally well be employed in any other systemrequiring augmentation of humidity.

An air inlet network or manifold 16, typically located after an airfilter (not shown), contains a hydrophilic membrane surface 18 thatseparates a water reservoir 20 from the air inlet network 16. The airinlet network 16 is coupled to a carburetor 21 containing a fuel feed 22incorporating a conventional needle valve 24 (the carburetor may, ofcourse, be replaced by any conventional fuel delivery system, forexample a fuel injection system or the like). The hydrophilic membranesurface 18 may be surrounded by a throttle (or hood/cowling) 26 thatregulates the area of hydrophilic membrane surface 18 exposed either tothe air inlet network 16 or the water reservoir 20. The throttle 26 canbe mechanically controlled, although in relation to an engine for a carit is more likely to be regulated by a microprocessor 28. As previouslydescribed, the carburetor 21 includes a Venturi tube configuration 30,which increases the velocity of air and encourages vaporization ofhydrocarbon fuel from the fuel feed 22. A fuel-air mixture 32 is thenfeed to inlet valves 34-36 in respective cylinder heads 38-40 of anengine cylinder block 42. For the sake of simplicity, a two-cylinderengine is shown by way of example in FIG. 1.

Of course, the water reservoir 20 could be remote from the hydrophilicmembrane, with only a feed pipe effectively providing a supply of waterto the surface of the hydrophilic membrane remote from any airpipe/inlet.

The surface of the hydrophilic membrane may be of any desired shape andmay be corrugated or flat, with the shape contributing to a maximumthroughput of pervaporate from the water reservoir. As will beappreciated, it is generally the rate at which water vapor is removedfrom the surface of the membrane (and the vapor pressure gradient acrossthe membrane) that determines the rate of pervaporation. Therefore, evenwhen the engine is not operating, some pervaporation takes place butthis is negligible and has no effect in view of there being no airmovement within the air intake system and the residual humidity withinthis form of open system.

Following the various stages of cylinder operation (such as induction,compression, ignition and expulsion), an outlet valve 44-46 associatedwith each cylinder 38-40 opens to expel exhaust gases (and to somelesser extent unburnt fuel) 48 to an exhaust system 50 of the motorizedvehicle 14. The exhaust system 50 may, optionally, feed into a heatexchanging coil 52 located in the water reservoir 20, with thetemperature of water in the water reservoir 20 increased by the hotexhaust gases. This is beneficial in two ways, first, the exhaust gasesare rendered relatively cooler (and hence less environmentally damaging)and second, the raised water temperature increases the rate of thepervaporation process through the hydrophilic membrane surface 18. Oncethe exhaust gases 48 have passed through the heat exchanging coil 52they are ejected from the motorized vehicle 14 (after additionalcleaning in a catalytic converter, for example) via an exhaust pipe.

Since the temperature of the water in the water reservoir shouldgenerally be limited to a specific operating range, a thermometer (orthe like) 54 provides temperature sensing information to themicroprocessor 28, with the microprocessor therefore able to regulateheating of the water with the opening and closing of a valve and by-passsystem 56. Alternatively or additionally, the temperature of the waterin the water reservoir may be adjusted by means of conventional heatingarrangements, for example, a microprocessor controlled heating coil. Ifhigh temperatures (e.g. 60.degree. C. or higher) are expected to bereached in the water reservoir, it may be necessary to provide a supportstructure for the hydrophilic membrane surface 18 as the membrane maysoften or deform if it is not supported, although this will, of course,depend upon the hydrophilic membrane materials selected.

During operation, water vapor pervaporates through the hydrophilicmembrane surface 18 and enters the air inlet stream. As the engines runsfaster, requiring an increased piston movement rate in each cylinder,the amount of water vapor taken from the surface of the membraneincreases accordingly, i.e. the system is self regulating according toair intake requirements, although the throttle 26 may further regulatethe amount of water vapor that is provided from the water reservoir 20.

Preferably, the water reservoir 20 is located within the engine at aposition such that should puncturing of the hydrophilic membrane occur,then water stored therein does not enter the engine. In such asituation, a loss of performance of the engine will inevitably result(in the same way as if the water reservoir were to run dry), but nodamage should be sustained by the engine. Clearly, should the waterlevel in the water reservoir 20 become low, then the microprocessor 28could alert the driver.

A further aspect that can complement or work independently of the systemof FIG. 1 involves the removal of water from a fuel tank 60 that feedsthe carburetor 21. The fuel tank 60 includes a hydrophilic membranesurface 62 that, preferably, is located in a floor 64 of the fuel tank60. With hydrocarbon fuel being lighter than water, any water present inthe fuel tank can therefore be purged from the fuel tank 60 via apervaporation process. Water vapor passing through the membrane 62 maybe passed directly back into the air inlet stream either by pumping orbecause the fuel tank 60 may be positioned so that the membrane 62delivers pervaporated water vapor directly into the air inlet 16.Alternatively, the water vapor may be condensed to liquid water 65 andcollected in a channel 16 that is coupled to the water reservoir 20 viaa pump 16. Such a system is particularly beneficial in relation todiesel engines, especially in a marine environment, with non-protecteddiesel engines otherwise susceptible to malfunction when water hasentered the diesel tank and has frozen. In this embodiment of theinvention, it will, of course, be necessary to select the materials fromwhich the hydrophilic membrane surface 62 is constructed carefully sothat the structure is not damaged by long term contact with the fuel andalso so that substantially none (or at least an insignificant amount) ofthe fuel (or components thereof) is transmitted across the membranesurface 62 into the induction air stream or the water reservoir 20.

In summary, the hydrophilic membrane 18 is used to spatially separateliquid water (including tap water and other forms of contaminated waterhaving organic or inorganic salts, suspensions or emulsions) from an airvolume inducted into an internal combustion engine 12 or the like. Thehydrophilic membrane acts to filter this liquid water so that only purewater pervaporates through the hydrophilic membrane. This pure watervapor is then continuously delivered into the induction air stream ofthe engine. The amount of pure water vapor delivered into the air streamis self-regulating, with more being delivered when the air stream movesacross the hydrophilic membrane at a faster rate.

In a second embodiment of the invention there is provided a fuel cellcomprising a humidifying gas induction or supply system having ahydrophilic membrane, particularly a proton exchange membrane fuel cell.

Proton exchange membrane fuel cells function by combining hydrogen andatmospheric or pure oxygen with the aid of a catalyst, generating usefulelectricity and water as a by-product across a proton exchange membraneand over a catalyst. Hydrogen functions as the anode and atmospheric orpure oxygen as the cathode. The current carrier that flows across theproton exchange membrane for the process of generating electricity is inthe form of protons. For the proton exchange membrane to functioneffectively, it needs to be kept moist, because water is needed totransport these protons across it (as H.sub.3 O.sup.+, rather thanH.sup.+) and so generate a current. Therefore, the higher the relativehumidity of the induction gases into a fuel cell, the greater theefficiency of this energy conversion device in producing electricity.

Humidification of the proton exchange membrane is achieved byhumidifying the induction hydrogen gas stream, and optionally by alsohumidifying the induction air or oxygen gas streams. The humidificationof hydrogen and air or oxygen induction streams may be performed byrecirculating the water generated as a by-production of the operation ofthe fuel cell, or additional water may be used separately.

Hydrogen gas in particular is normally available in compressed form ingas bottles and contains very little moisture. The air or oxygen used asthe other induction gas stream may also need to be humidified; dependingon their initial water content. As the induction gas flows of hydrogenand air or oxygen are increased to generate more and more electricity,humidification of the hydrogen in particular become more and moredifficult, leading to a reduction in the efficiency of the fuel cell athigher power density.

Existing methods of humidification of the induction gas streams useexpensive membrane materials and are complicated, so there is a criticalneed for an effective humidification system at low cost.

An additional embodiment of this invention is therefore given by the useof hydrophilic membranes to separate the induction, dry gas streams,both hydrogen and oxygen or air, from the wet, oxygen-depleted airexhaust gas stream, so that water may pervaporate through thehydrophilic membrane from the wet exhaust air into the dry inductionhydrogen and air or oxygen streams. The self-regulating function ofhydrophilic membranes allows more water to pervaporate through themembrane when there is a high gas flow, which is precisely what isrequired.

FIG. 2 shows a schematic view of a fuel cell 100, where the dry hydrogengas stream 102 is humidified by being in contact with a hydrophilicmembrane 104 which is contacted, on the other face, with the wet exhaustair 106. Water will therefore pervaporate across the hydrophilicmembrane 104 and humidify the hydrogen gas stream 102 before it reachesthe fuel cell.

Optionally, an additional hydrophilic membrane 108 may be used,separating the hydrogen gas stream 102 from a container 110 filled withliquid water 112. Should the humidity from the exhaust air stream not besufficient for the humidification of the hydrogen gas stream, more watermay be provided by pervaporation through the hydrophilic membrane 108 inthis optional additional arrangement.

FIG. 3 shows a schematic view of a further embodiment of the fuel cellof the invention, where not only the dry hydrogen gas stream 102 ishumidified but also the air or oxygen gas stream 114. In a similarmanner to the way in which the hydrogen gas stream 102 is humidified,the air or oxygen gas stream 114 is in contact with a hydrophilicmembrane 116, which is contacted, on the other face, with the wetexhaust air 106. Water will therefore pervaporate across the hydrophilicmembrane 116 and humidify the air or oxygen gas stream 114 before itreaches the fuel cell 100.

As shown in FIG. 3, an optional additional hydrophilic membrane 118 mayalso be used, separating the air or oxygen gas stream 114 from acontainer 120 filled with liquid water 122. Should the humidity from theexhaust air stream not be sufficient for the humidification of the airor oxygen gas stream 114, more water may be provided by pervaporationthrough the hydrophilic membrane 118 in this optional additionalarrangement.

The amount of water released from the optional additional hydrophilicmembranes (108 and 118) may optionally be controlled, for example, byheating the water in the associated containers (110 and 120) or byproviding a hood arranged to regulate the area of hydrophilic membranesurface exposed to the induction hydrogen, oxygen or air streams.

Optionally, the hydrophilic membranes 18, 104, 108, 116, 118 in anembodiment of the invention may be shaped to ensure a maximum surfacearea in contact with induction gas in a minimal space (e.g. fluted orconvoluted shapes).

In the context of the disclosure, hydrophilic membranes for use in thehumidifying gas induction or supply system of the present invention maybe made from hydrophilic polymers. The term “hydrophilic polymer” meansa polymer that absorbs water when in contact with liquid water at roomtemperature according to International Standards Organizationspecification ISO 62 (equivalent to the American Society for Testing andMaterials specification ASTM D 570).

The hydrophilic polymer can be one or a blend of several polymers. Forexample, the hydrophilic polymer could be a copolyetherester elastomeror a mixture of two or more copolyetherester elastomers, such aspolymers available from E.I. du Pont de Nemours and Company under thetrade name HYTREL®. Alternatively, the hydrophilic polymer could bepolyether-block polyamide or a mixture of two or more polyether-blockpolyamides, such as the polymers from Elf-Atochem Company of Paris,France available under the name PEBAX™. Other hydrophilic polymersinclude polyether urethanes or a mixture thereof, homopolymers orcopolymers of polyvinyl alcohol and mixtures thereof. The above list isnot considered to be exhaustive, but merely exemplary of possiblechoices of hydrophilic polymers.

A particularly preferred polymer for water vapor transmission in thisinvention is a copolyetherester elastomer or mixture of two or morecopolyetherester elastomers having a multiplicity of recurringlong-chain ester units and short-chain ester units joined through esterlinkages, said long-chain ester units being represented by the formula:

and said short-chain ester units are represented by the formula:

wherein:

-   -   a) G is a divalent radical remaining after removal of terminal        hydroxyl groups from a poly(alkylene oxide)glycol having an        average molecular weight of about 400-4000;    -   b) R is a divalent radical remaining after removal of carboxyl        groups from a dicarboxylic acid having a molecular weight less        than about 300;    -   c) D is a divalent radical remaining after removal of hydroxyl        groups from a diol having a molecular weight less than about        250; optionally    -   d) the copolyetherester contains 0-68 weight percent, based on        the total weight of the copolyetherester, ethylene oxide groups        incorporated in the long-chain ester units of the        copolyetherester;    -   e) the copolyetherester contains about 25-80 weight percent        short-chain ester units.

The preferred polymer film is suitable for fabricating into thin butstrong membranes, films and coatings. The preferred polymer,copolyetherester elastomer and methods of making it are known in theart, such as disclosed in U.S. Pat. No. 4,725,481 for a copolyetheresterelastomer with a WVTR of 3500 g/m.sup.2/24 hr, or U.S. Pat. No.4,769,273 for a copolyetherester elastomer with a WVTR of 400-2500g/m.sup.2/24 hr.

The use of commercially available hydrophilic polymers as membranes ispossible in the context of the present invention, although it is clearlypreferable to have as high a WVTR as possible so as to minimize thesurface area of hydrophilic membrane necessary to provide a given amountof water in the gas intake. Most preferably, the present invention usescommercially available membranes that yield a WVTR of more than 3500g/m.sup.2/24 hr, measured on a film of thickness 25 microns using air at23.degree. C. and 50% relative humidity at a velocity of 3 ms.sup.−1.

The polymer can be compounded with antioxidant stabilizers, ultravioletstabilizers, hydrolysis stabilizers, dyes, pigments, fillers,anti-microbial reagents and the like.

A useful and well-established way to make membranes in the form of filmsis by melt extrusion of the polymer on a commercial extrusion line.Briefly, this entails heating the polymer to a temperature above itsmelting point and extruding it through a flat or annular die and thencasting a film using a roller system or blowing the film from the melt.Support materials may be used in constructing the membrane and caninclude woven, non-woven or bonded papers, fabrics and screens andinorganic polymers stable to moisture, such as polyethylene,polypropylene, fiberglass and the like. The support material bothincreases strength and protects the membrane.

The support material may be disposed on only one side of the hydrophilicpolymer membrane, or on both sides. When disposed on only one side, thesupport material can be in contact with the water or away from it.

Without being bound by any particular theory, it is believed that thepurifying effect of the hydrophilic membrane, realized either in theform of a coating or an unsupported membrane, when in contact with waterthat may contain suspended or dissolved impurities, solids andemulsions, occurs because highly dipolar molecules, such as water, arepreferentially absorbed and transported across the membrane or coating,compared to ions, such as sodium and chloride. When, in addition, avapor pressure gradient exists across the membrane, water is releasedfrom the side not in contact with the source of water.

In relation to the hydrophilic membranes used in the preferredembodiments of the present invention, the water transmissioncharacteristics are generally determined using standard test procedureASTM E96-95-Procedure BW (previously known and named as test procedureASTM E96-66-Procedure BW). These standard test procedures are used todetermine the water vapor transmission rate (WVTR) of a membrane, anduse an assembly based on a water-impermeable cup (i.e. a “Thwing-AlbertVapometer”). The water-impermeable cup contains water to a level aboutnineteen millimeters below the top of the cup (specifically, 19mim.+−0.6 mm). The opening of the cup is sealed watertight with awater-permeable membrane of the test material to be measured, leaving anair gap between the water surface and the membrane. In procedure BW, thecup is then inverted so that water is in direct contact with themembrane under test. The apparatus is placed in a test chamber at acontrolled temperature and humidity, and air is then blown across theoutside of the membrane at a specified velocity. Experiments are run induplicate. The weights of the cups, water and membrane assemblies aremeasured over several days and results are averaged. The rate at whichwater vapor permeates through the membrane is quoted as the “watertransmission vapor rate”, measured as the average weight loss of theassembly at a given membrane thickness, temperature, humidity and airvelocity, as expressed as mass loss per unit membrane surface area andtime. The WVTR of membranes or films according to ASTM E96-95-ProcedureBW is typically measured on a film of thickness twenty five microns andat an air flow rate of three meters per second (3 ms.sup.−1), airtemperature twenty three degrees Celsius (23.degree. C.) and fiftypercent (50%) relative humidity.

It will, of course, be appreciated that the above description has beengiven by way of example only and that modifications in detail may bemade within the scope of the present invention. For example, whilst thepreferred embodiment of FIG. 1 is specifically described in relation toa two-cylinder car engine, the air intake system could be employed tosupply any engine. Indeed, the location of the humidity augmentingnon-porous membrane can be at one of a number of alternative positionswithin the engine, including at any stage before or after and airfilter, at a point after the fuel-air mixture is formed in an inletmanifold or even in the cylinder itself.

Clearly, the use of a non-porous hydrophilic membrane is most preferredsince its inherent nature limits the passage of water vapor into theinlet system, while not suffering from any clogging by dirt or debrisbecause it is not porous. Moreover, a non-porous hydrophilic membraneguarantees that this part of the air induction system is hermeticallysealed from the water source, which will therefore not be affected bythe normal operating range of air pressure within the air inductionsystem during the operation of the engine.

1. A fuel cell comprising a humidifying gas induction or supply systemhaving a non-porous hydrophilic membrane, wherein said non-poroushydrophilic membrane has at least two faces; the first face being incontact with a hydrogen gas stream and the second face being in contactwith wet exhaust air wherein said non-porous hydrophilic membraneabsorbs liquid water from the wet exhaust air and transports watermolecules across the non-porous hydrophilic membrane surface so as toemerge into the hydrogen gas stream as water vapor.
 2. The fuel cellaccording to claim 1 having at least a second non-porous hydrophilicmembrane, the second non-porous hydrophilic membrane having at least twofaces; the first face being in contact with the hydrogen gas stream andthe second face being in contact with a container of liquid water,wherein said non-porous hydrophilic membrane absorbs liquid water fromthe container and transports water molecules across the secondnon-porous hydrophilic membrane so as to emerge into the hydrogen gasstream as water vapor.
 3. The fuel cell according to claim 1 having atleast a third non-porous hydrophilic membrane having at least two faces;the first face being in contact with an air or oxygen gas stream and thesecond face being in contact with wet exhaust air wherein saidnon-porous hydrophilic membrane surface absorbs liquid water from thewet exhaust air and transports water molecules across said thirdnon-porous hydrophilic membrane so as to emerge into the air or oxygengas stream as water vapor.
 4. The fuel cell according to claim 2 havingat least a third non-porous hydrophilic membrane, said third non-poroushydrophilic membrane having at least two faces; the first face being incontact with an air or oxygen gas stream and the second face being incontact with wet exhaust air wherein said non-porous hydrophilicmembrane absorbs liquid water from the wet exhaust air and transportswater molecules across said third non-porous hydrophilic membrane so asto emerge into the air or oxygen gas stream as water vapor.
 5. The fuelcell according to claim 3 having at least a fourth non-poroushydrophilic membrane, said fourth non-porous hydrophilic membrane havingat least two faces; the first face being in contact with the air oroxygen gas stream and the second face being in contact with a containerof liquid water wherein said non-porous hydrophilic membrane absorbsliquid water from the wet exhaust air and transports water moleculesacross the fourth non-porous hydrophilic membrane from the container ofliquid water so as to emerge into the air or oxygen gas stream as watervapor.
 6. The fuel cell according to claim 4 having at least a fourthnon-porous hydrophilic membrane, said fourth non-porous hydrophilicmembrane having at least two faces; the first face being in contact withthe air or oxygen gas stream and the second face being in contact with acontainer of liquid water wherein said non-porous hydrophilic membraneabsorbs liquid water from the wet exhaust air and transports watermolecules across the fourth non-porous hydrophilic membrane from thecontainer of liquid water so as to emerge into the air or oxygen gasstream.
 7. The fuel cell according to claim 1, wherein there is a vaporpressure gradient across said first face and said second face of saidnon-porous hydrophilic membrane, such that liquid water is absorbed bysaid second face and water molecules are transported through and out ofsaid first face.
 8. The fuel cell according to claim 2, wherein there isa vapor pressure gradient across said first face and said second face ofsaid non-porous hydrophilic membrane, such that liquid water is absorbedby said second face and water molecules are transported through and outof said first face.
 9. The fuel cell according to claim 3, wherein thereis a vapor pressure gradient across said first face and said second faceof said non-porous hydrophilic membrane, such that liquid water isabsorbed by said second face and water molecules are transported throughand out of said first face.
 10. The fuel cell according to claim 5,wherein there is a vapor pressure gradient across said first face andsaid second face of said non-porous hydrophilic membrane, such thatliquid water is absorbed by said second face and water molecules aretransported through and out of said first face.